1. Field of the Invention
The present invention relates to a backlight unit and a liquid crystal display having the same, and more particularly, to a backlight unit and a liquid crystal display having the same on which a point light source is efficiently disposed.
2. Description of the Related Art
Recently, flat panel display apparatuses, such as LCD (liquid crystal display), PDP (plasma display panel), and OLED (organic light emitting diode) display types, has been developed in place of a CRT (cathode ray tube) display type.
A typical liquid crystal display (hereinafter referred to as ‘LCD’) comprises an LCD panel having a TFT substrate, a color filter substrate, and a liquid crystal layer disposed between the two substrates. Since the liquid crystal layer does not emit light, the LCD may comprise a backlight unit disposed in rear of the TFT substrate. The amount of light emitted from the backlight unit which is transmitted through the liquid crystal is adjusted according to an alignment of the liquid crystals in the liquid crystal layer. The LCD panel and the backlight unit are provided in a chassis.
Depending on the location of the light source, the backlight unit may be an edge type or a direct type backlight unit. The edge type provides the light source at a lateral side of a light guiding plate and is typically used for a relatively small LCDs, such as those used in laptops and desktop computers. The edge type provides a high light uniformity and a good endurance, and is suitable for use in thin profile LCDs.
As a result of the increasing size of LCD displays in the market, the development of the direct type backlight unit has been emphasized. The direct type backlight unit provides the entire surface of the LCD with light by disposing a plurality of light sources in the rear of the LCD panel. The direct type backlight unit provides a high level of brightness by using a plurality of light sources, as compared with the edge type backlight unit, but the brightness is generally not sufficiently uniform.
The LED, which is a point light source, rather than a linear light source, such as a lamp, has been identified as a suitable light source for direct type backlight units, due to its high brightness and an excellent color reproducibility. A series of LEDs are generally seated on an LED circuit board in a line, and a plurality of LED circuit boards are disposed in rear of the LCD panel in parallel rows.
However, in LCDs utilizing the above-described arrangement, the brightness is high directly above the LED circuit board, but is not as high in the regions between adjacent LED circuit boards. Thus, the uniformity of the brightness of the LCD panel may be decreased.